JP7358282B2 - linear drive - Google Patents

Description

Embodiments of the invention relate to linear drives.

2. Description of the Related Art Generally, linear drive devices are known in which a shaft is linearly moved by rotational force from a motor. For example, a linear drive device that uses an American winding stop mechanism to regulate the linear movement stroke of a movable shaft has been disclosed (see Patent Document 1).

Patent No. 4136333

However, when a linear drive device is provided with a structure that restricts the linear motion of the shaft, sufficient consideration is not given to returning the shaft from the restricted state to normal linear motion.

An object of embodiments of the present invention is to provide a linear drive device that limits the linear movement of an axis and that allows the axis to easily return to normal linear movement from the restricted state.

According to the embodiments of the present invention, it is possible to provide a linear drive device that restricts the linear movement of an axis and that allows the axis to easily return to normal linear movement from the restricted state.

A linear drive device according to an embodiment of the present invention includes a motor, a shaft that rotates by the rotational force of a rotor of the motor, passes through a rotation center portion of the rotor, and operates in a thrust direction with respect to the rotor; a plate-shaped flange with a shaft fixed to the center; a first stopper provided on at least one of the front surface or the back surface of the flange; a second stopper that limits movement beyond the lower point, and at least one of the first stopper and the second stopper contacts the other at an inclined surface.

1 is a vertical cross-sectional view of the configuration of a linear drive device according to a first embodiment of the present invention; FIG. FIG. 2 is a perspective view showing the configuration of a shaft according to the first embodiment. FIG. 3 is a horizontal cross-sectional view of the axial movement limiting section according to the first embodiment. FIG. 3 is a plan view showing the back surface of the flange according to the first embodiment. FIG. 3 is a vertical cross-sectional view of the configuration of a linear drive device according to a second embodiment of the present invention. FIG. 7 is a plan view showing the back surface of the flange according to the second embodiment. FIG. 7 is a vertical cross-sectional view of the configuration of a linear drive device according to a third embodiment of the present invention. FIG. 7 is a plan view showing the back surface of the flange according to the third embodiment.

(First embodiment)
FIG. 1 is a vertical cross-sectional view of the configuration of a linear drive device 10 according to a first embodiment of the present invention. FIG. 2 is a perspective view showing the configuration of the shaft 1 according to this embodiment. In the drawings, the same parts are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.
The linear drive device 10 includes a shaft 1 , a rotor 2 , a coil 3 , a yoke 4 , a mounting plate 5 , a nut 6 , two bearings 7 and 8 , and a shaft motion restriction section 20 . Note that, as shown in FIG. 3, the linear drive device 10 may include a connector section 9 that electrically connects wiring for supplying power or transmitting and receiving electrical signals. Here, the description will be made assuming that the shaft movement limiting portion 20 side is on top and the nut 6 side is on the bottom.

By operating in the thrust direction, the shaft 1 presses an object to be operated by the linear drive device 10 with a ball 11 provided at the lower end. The shaft 1 has a shape in which an upper portion 1a and a lower portion 1b are integrally coupled. The shaft 1 has a rod shape that extends through the entire linear drive device 10 in the vertical direction. The cross section of the upper portion 1a has an oval shape, such that both ends of a circle are D-cut. The cross section of the lower part 1b is circular. A ball 11 is provided at the tip of the lower portion 1b. A male thread 12 is formed on the side surface of the tip portion of the lower portion 1b. The male thread 12 may be formed on all the side surfaces of the lower portion 1b.

The rotor 2, coil 3, and yoke 4 constitute a motor. A plurality of coils 3 are arranged inside the yoke 4 so as to face the outer peripheral surface of the rotor 2 . By energizing the coil 3, the rotor 2 rotates and a rotational force is applied to the shaft 1. For example, the motor is a claw pole type PM (permanent magnet) motor.

A magnet is provided on the outer peripheral surface of the rotor 2 so as to face the coil 3. The rotor 2 has a cylindrical rotation center portion provided with a hole through which the shaft 1 passes. The hole provided on the upper side of the rotor 2 is arranged so that the upper part 1a of the shaft 1 can move in the thrust direction and transmit the rotational force of the rotor 2 to the shaft 1. It is formed into an oval shape with a large circumference. The hole provided on the lower side of the rotor 2 is formed in a circular shape that is one size larger than the cross section of the lower portion 1b of the shaft 1 so that the lower portion 1b of the shaft 1 can move in the thrust direction.

The mounting plate 5 has a plate shape and is attached to the lower surface of the yoke 4. A hole through which the shaft 1 passes and a hole for attaching a nut 6 are provided in the center of the mounting plate 5. The mounting plate 5 may be provided with a shape for mounting the linear drive device 10 on another device so as to extend in the radial direction from the outer periphery.

The nut 6 is attached to the lower surface of the yoke 4 via the attachment plate 5. The nut 6 has a cylindrical shape with a hole passing through the center, and the outer periphery of the lower surface is tapered. A female thread 61 is formed on the inner circumferential surface of the lower part of the hole of the nut 6 so as to mesh with the male thread 12 provided at the lower end of the shaft 1. The upper part of the hole in the nut 6 has a wider diameter than the lower part so that a space is formed. A bearing 7 is provided in a space formed in the upper part of the nut 6.

The bearings 7 and 8 are bearings that suppress fluctuations of the shaft 1 in the radial direction. Note that the bearings 7 and 8 may have any configuration.

The shaft motion restriction section 20 includes a mechanism that restricts the shaft 1 from moving in the thrust direction beyond a predetermined range. The shaft motion limiting section 20 is provided on the side opposite to the side on which the shaft 1 acts (the ball 11 side).

The axial motion restriction section 20 includes a case 21, a cover 22, a flange 23, and stoppers 24a, 24b, 25a, and 25b. Note that in FIG. 1, each of the stoppers 24a to 25b is shown one by one for convenience of explanation.

FIG. 3 is a horizontal cross-sectional view of the shaft motion limiting section 20 according to the first embodiment, showing the bottom surface of the case 21. As shown in FIG. FIG. 4 is a plan view showing the back surface of the flange 23 according to the first embodiment.

The case 21 covers the side and bottom surfaces of the shaft motion restriction section 20 . Case 21 is attached to the upper surface of yoke 4. The case 21 has a cylindrical shape, and a hole H1 through which the shaft 1 moves in the thrust direction is closed at a bottom surface provided in the center. A plurality of stoppers 25a are arranged on the bottom surface of the case 21 in a circumferential direction so as to surround the outer periphery of the hole H1. The outer peripheral portion of the upper surface of the case 21 is provided with a groove or the like into which the cover 22 is fitted. The case 21 may be provided with a hole or shape for attaching the bearing 8 or the like.

The cover 22 is attached to cover the upper surface of the case 21. The cover 22 has a disk shape, and is provided with a hole in the center thereof through which the shaft 1 moves in the thrust direction. On the back surface of the cover 22, like the bottom surface of the case 21, a plurality of stoppers 25b are arranged in the circumferential direction so as to surround the outer periphery of the hole through which the shaft 1 passes. The cover 22 may be formed integrally with the case 21, or may be attached so as to cover the bottom surface of the case 21.

The flange 23 has a disk shape, and a hole H2 through which the shaft 1 passes is provided in the center. Note that the outer shape of the flange 23 is not limited to a circle, and may have any shape as long as it is plate-shaped. The flange 23 is fixedly attached to the shaft 1. On the back surface of the flange 23, a plurality of stoppers 24a are arranged in the circumferential direction so as to surround the outer periphery of the hole H2, corresponding to the plurality of stoppers 25a provided on the bottom surface of the case 21, respectively. Similarly, a plurality of stoppers 24b are provided on the upper surface of the flange 23, corresponding to the plurality of stoppers 25b provided on the back surface of the cover 22, and arranged in the circumferential direction so as to surround the outer periphery of the hole H2.

Hereinafter, the structure of the stopper 24a provided on the bottom surface of the flange 23 and the stopper 25a provided on the bottom surface of the case 21 will be mainly explained, and the structure of the stopper 24b provided on the top surface of the flange 23 and the back surface (inner side) of the cover 22 will be mainly explained. ) The structure with the stopper 25b provided in ) is assumed to be the same, and a description thereof will be omitted as appropriate. Moreover, one set of stoppers 24a, 25a will be mainly explained, and the descriptions of the other stoppers 24a, 25a will be omitted as appropriate, assuming that they are similarly configured.

The surface (horizontal cross section) of the stopper 24a has a shape in which the sides corresponding to the upper and lower bases of a trapezoid are arcs, and the shorter arc is located on the inner circumferential side. The stoppers 24a are arranged so that two concentric circles are drawn by connecting two arcs corresponding to the upper and lower bases of all the stoppers 24a. A hole H2 through which the shaft 1 passes is located at the center of these concentric circles. The same applies to the shape and arrangement of the stopper 25a.

As shown in FIG. 1, in a cross section of the stopper 24a taken perpendicular to the radial direction of the flange 23 and perpendicular to the horizontal direction, position P2 is the highest apex (the lowest point in FIG. 1), and position P1 is the highest apex (lowest point in FIG. 1). It becomes a right triangle with the lowest apex (the uppermost point in Figure 1). The position P1 is at the same height as the back surface of the flange 23 on which the stopper 24a is not provided. That is, the surface of the stopper 24a is formed into a slope that increases from position P1 to position P2.

As shown in FIG. 1, the cross section of the stopper 25a cut perpendicular to the radial direction of the bottom surface of the case 21 and perpendicular to the horizontal direction is a right triangle with the highest apex at position P4 and the lowest apex at position P3. Become. The position P3 is at the same height as the part of the bottom surface of the case 21 where the stopper 25a is not provided. That is, the surface of the stopper 25a is formed into a slope that increases from position P3 to position P4. The inclination of this stopper 25a is the same angle as the inclination of the stopper 24a.

Here, the two stoppers 24a and 25a have their slopes in close contact with each other when the shaft 1 is located at the lowest point in a predetermined range in the thrust direction, and the flange 23 prevent it from rotating. Further, before the shaft 1 is located at the lowest point in a predetermined range in the thrust direction, the highest position P2 of the stopper 24a and the highest position P4 of the stopper 25a are prevented from coming into contact even if the flange 23 rotates. Specifically, the highest positions P2 and P4 of the two stoppers 24a and 25a do not come into contact with each other before the flange 23 rotates one rotation from the state where the shaft 1 is located at the lowest point in a predetermined range in the thrust direction. It is sufficient if the flange 23 can be rotated without any movement.

Next, the role of the stopper 24a and the stopper 25a as a stopper will be explained. FIG. 1 shows a configuration in which the male screw 12 of the shaft 1 is formed as a right-handed screw (a screw that goes deeper when turned clockwise), and the stoppers 24a and 25a corresponding to each other are arranged in front of the shaft 1.

When the shaft 1 is located at the lowest point in a predetermined range in the thrust direction, the slopes of the corresponding stoppers 24a and 25a come together, and the rotation of the flange 23 is stopped.

Specifically, when the flange 23 attempts to continue rotating with the slopes of the stoppers 24a and 25a in contact with each other, the highest position P2 of the stopper 24a and the highest position P4 of the stopper 25a move toward each other. try to work. However, the highest position P2 of the stopper 24a and the highest position P4 of the stopper 25a cannot overcome each other. Further, when the flange 23 tries to rotate, the frictional force between the slopes of the two stoppers 24a and 25a increases, so the flange 23 stops rotating.

This also stops the rotation of the shaft 1 to which the flange 23 is fixed, so that the shaft 1 no longer moves downward.

On the other hand, when the shaft 1 is at its lowest point, the flange 23 is rotated in the opposite direction so that the shaft 1 moves upward from a state where the rotation of the flange 23 is stopped due to the frictional force between the slopes of the two stoppers 24a and 25a. Let me explain what happens when you start doing this. In this case, the highest position P2 of the stopper 24a and the highest position P4 of the stopper 25a tend to move away from each other. At this time, since the two stoppers 24a and 25a are in contact with each other at their slopes, the frictional force between the two stoppers 24a and 25a is instantly reduced sharply as the flange 23 starts to rotate in the opposite direction.

As a result, even when the shaft 1 is stopped at the lowest point by the two stoppers 24a and 25a, the flange 23 can easily start rotating in the opposite direction, and the shaft 1 can quickly move upward. can.

The stopper 24a provided on the bottom surface of the flange 23 and the stopper 25a provided on the bottom surface of the case 21 serve as a stopper at the lowest point of a predetermined range in the thrust direction of the shaft 1, whereas The stopper 24b provided on the rear surface of the cover 22 and the stopper 25b provided on the back surface of the cover 22 serve as a stopper at the uppermost point of a predetermined range in the thrust direction of the shaft 1. In other respects, the stoppers 24b and 25b are the same as the stoppers 24a and 25a.

Note that if it is not necessary to limit the lowest point of the shaft 1, the stoppers 24a and 25a that contact on the lower side may be removed. Furthermore, if it is not necessary to limit the uppermost point of the shaft 1, the stoppers 24b and 25b that contact on the upper side may be removed.

According to this embodiment, by providing the stoppers 24a to 25b whose slopes come into contact with each other to stop the rotation of the flange 23, the linear motion of the shaft 1 in the thrust direction is limited within a predetermined range, and the stopper 24a .about.25b can make it easier for the shaft 1 to return to normal linear motion from a stopped state.

In this embodiment, all the stoppers 24a to 25b are brought into contact with each other at their slopes, but if at least one of the contact surfaces of the stoppers 24a to 25b that contact each other is a slope, the other contact surface is not a slope. Even when the shaft 1 is stopped, the shaft 1 can be easily returned to normal linear motion from a stopped state.

(Second embodiment)
FIG. 5 is a vertical cross-sectional view of the configuration of a linear drive device 10A according to a second embodiment of the present invention. FIG. 6 is a plan view showing the back surface of the flange 23 according to the second embodiment.

The linear drive device 10A is the linear drive device 10 according to the first embodiment shown in FIG. 1, in which the shaft motion restriction section 20 is replaced with an shaft motion restriction section 20A. The axial motion limiting section 20A is obtained by replacing the stoppers 24a and 24b provided on the flange 23 of the axial motion limiting section 20 according to the first embodiment with stoppers 24aA and 24bA having elastic bodies 26 attached to the slopes thereof. . In other respects, the linear drive device 10A is the same as the first embodiment.

The elastic body 26 is attached to the slopes of the stoppers 24aA, 24bA so as to be interposed between the slopes of the stoppers 24aA, 24bA when the slopes of the stoppers 24a, 24bA are joined to the corresponding stoppers 25a, 25b. The elastic body 26 may be any material as long as it generates a repulsive force so that it expands after being crushed. For example, the elastic body 26 is a substance such as rubber or sponge that generates a repulsive force due to its material or shape. Further, the elastic body 26 may have any shape, but is preferably spherical from the viewpoint of generating a constant repulsive force no matter which direction it is crushed.

Note that the elastic body 26 may be provided on the stoppers 25a and 25b on the cover 22 or case 21 side. In this case, the elastic body 26 may or may not be provided on the stoppers 24aA, 24bA on the flange 23 side.

According to the present embodiment, by providing the stoppers 24aA and 24bA to which the elastic body 26 is attached, in addition to the effects of the first embodiment, the repulsive force of the elastic body 26 causes the stoppers 24aA to 25b to stop the shaft 1. Returning from the state to normal linear operation can be made easier than in the first embodiment.

(Third embodiment)
FIG. 7 is a vertical cross-sectional view of the configuration of a linear drive device 10B according to a third embodiment of the present invention. FIG. 8 is a plan view showing the back surface of the flange 23 according to the third embodiment.

The linear drive device 10B is the linear drive device 10 according to the first embodiment shown in FIG. 1 in which the shaft motion restriction section 20 is replaced with an shaft motion restriction section 20B. The axial motion limiting section 20B is obtained by replacing the stoppers 24a and 24b provided on the flange 23 of the axial motion limiting section 20 according to the first embodiment with stoppers 24aB and 24bB. In other respects, the linear drive device 10B is the same as the first embodiment.

The stoppers 24aB, 24bB are elastic bodies such as leaf springs provided so that the contact points are in contact with the slopes of the corresponding stoppers 25a, 25b. The stoppers 24aB, 24bB may be made of any material or shape as long as they are elastic bodies that come into close contact with the stoppers 25a, 25b and generate a repulsive force.

Next, the functions of the stoppers 24aB and 24bB will be explained.
When the flange 23 further rotates after the contact points of the stoppers 24aB, 24bB contact the stoppers 25a, 25b, the stoppers 24aB, 24bB come into closer contact with the stoppers 25a, 25b while storing potential energy due to elastic force. As a result, the rotation of the flange 23 gradually weakens. Thereafter, when the stoppers 24aB, 24bB come into close contact with the stoppers 25a, 25b in a sufficiently curved state, the rotation of the flange 23 is stopped. At this time, axis 1 is at one end (the highest point or the lowest point) of the predetermined range.

Next, when the shaft 1 begins to move in the opposite direction, the stops 24aB, 24bB begin to move away from the stops 25a, 25b. At this time, a repulsive force acts due to the potential energy due to the elastic force stored in the stoppers 24aB, 24bB, and the stoppers 24aB, 24bB tend to separate from the stoppers 25a, 25b.

Note that instead of the stoppers 24aB, 24bB on the flange 23 side, the stoppers 25a, 25b on the cover 22 or case 21 side may be replaced with elastic bodies such as leaf springs.

According to this embodiment, by providing the stoppers 24aB and 24bB like leaf springs, in addition to the effects of the first embodiment, the stoppers 24aB to 25b are Returning the shaft 1 from a stopped state to normal linear motion can be made easier than in the first embodiment.

Note that the present invention is not limited to the embodiments described above, and constituent elements may be deleted, added, or changed. Even if such embodiments are directly different from the embodiments described above, those having the same meaning as the present invention are treated as embodiments of the present invention, and the explanation thereof will be omitted.

DESCRIPTION OF SYMBOLS 1... Shaft, 2... Rotor, 3... Coil, 4... Yoke, 5... Mounting plate, 6... Nut, 7, 8... Bearing, 10... Linear drive device, 20... Axis motion restriction part.

Claims (6)

motor and
a shaft that rotates by the rotational force of a rotor of the motor, passes through a rotation center portion of the rotor, and operates in a thrust direction with respect to the rotor;
a plate-shaped flange with the shaft fixed to the center;
a first stopper provided on at least one of the front surface or the back surface of the flange;
a second stopper that contacts the first stopper and limits movement of the shaft beyond the highest or lowest point of a predetermined range;
A linear drive device characterized in that at least one of the first stopper and the second stopper contacts the other at an inclined surface. The linear drive device according to claim 1, wherein the first stopper and the second stopper each include the slope, and are in contact with each other so that the slopes are brought together. The linear drive device according to claim 1, wherein at least one of the first stopper and the second stopper includes an elastic body provided on the slope. The linear drive device according to claim 3, wherein the elastic body is spherical. 2. At least one of the first stopper and the second stopper includes an elastic body such as a leaf spring, and is in contact with the other slope so as to store potential energy due to elastic force. linear drive. The first stopper is provided on each of the front and back surfaces of the flange,
The second stopper is provided corresponding to each of the first stoppers, and contacts each of the first stoppers to limit the movement of the shaft beyond the uppermost point or the lowermost point of a predetermined range. The linear drive device according to claim 1.

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